Beta-Cyclodextrin-Grafted PVA Hydrogel Containing Benzene Sulfonamide

Beta-Cyclodextrin (beta-CD)-grafted poly(vinyl alcohol) (PVA) hydrogel was prepared by cross-linking beta-CD and PVA using epichlorohydrin (EPI), where the molar ratios of EPI to beta-CD were 4:1, 7:1 and 10:1. In order to endow a pH-sensitivity to the hydrogel, benzene sulfonamide was loaded in the hydrogel by taking advantage of its hydrophobic interaction with the cavities of beta-CD. beta-CD-grafted PVA polymers were characterized by Fourier Transform Infrared Spectrometry (FT-IR) and 1H-NMR. The number of beta-CD residues grafted on PVA chain was calculated from 1H-NMR. The benzene sulfonamide will be strongly electrostatically charged under an acidic condition. So the hydrogel would swell due to the electrostatic repulsion among benzene sulfonamide molecules, promoting the release under an acidic condition.